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1.
地质样品铜、铁、锌同位素标准物质的研制   总被引:10,自引:0,他引:10       下载免费PDF全文
合适的标准物质是进行同位素准确分析的基础和关键,本文介绍了基于地质样品的铜、铁、锌同位素分析标准参考物质的研制过程.所研制的标准物质为CAGSR-1,用于该标准物质研制的原始样品为玄武质组分的岩石成分分析国家标准物质GBW07105.按照国家一级标准的要求,对该标准物质进行了严格的均一性、稳定性检验和同位素定值分析.标准物质CAGSR-1的主要特性量值δ65Cu、δ56Fe、δ66Zn的推荐值及95%置信水平的不确定度为:δ65CuSRM976(‰)=0.10±0.02、δ56FeIRMM014(‰)=0.12±0.02、δ66ZnRomil(‰)=7.45±0.01.该标准物质可用于地质与环境样品铜、铁、锌同位素测定中化学流程评价和验证、质谱仪的校正及整个过程的分析质量控制.  相似文献   

2.
近十来年铁铜锌同位素研究已经成为热门研究领域,铁铜锌同位素分析方法日趋成熟,但是铁铜锌同位素标准物质却十分匮乏。目前欧盟参考物质及测量研究所(IRMM)有1个铁同位素标准物质和1个锌同位素标准物质,前者售罄,后者价格昂贵;美国国家标准局(NIST)有1个铜同位素标准物质。为了适应我国铁铜锌同位素研究的发展,本文使用铁铜锌元素浓度标准溶液作为备选标准溶液研制了铁铜锌三个同位素标准溶液(CAGS-Fe、CAGS-Cu和CAGS-Zn)。三个备选标准溶液经过F检验均匀性良好;在38个月内δ56Fe、δ57Fe、δ65Cu、δ66Zn和δ68Zn值没有显著性变化,具有良好的稳定性;主要特性值的推荐值及95%置信水平的不确定度为:CAGS-Fe,δ56FeIRMM014(‰)=0.80±0.05,δ57FeIRMM014(‰)=1.20±0.10;CAGS-Cu,δ65CuIRMM976(‰)=0.57±0.06;CAGS-Zn,δ66ZnIRMM3702(‰)=-0.77±0.10,δ68ZnIRMM3702(‰)=-1.55±0.13。本文研制的标准溶液可用于多接收器等离子体质谱仪测定铁铜锌同位素时的仪器校正和质谱分析过程监控,对于不同实验室的测试数据对比具有重要意义。  相似文献   

3.
<正>大量研究表明,上地幔铁同位素组成是不均一的,上地幔平均值为δ56Fe=0.025±0.025‰[1]。玄武岩具有比上地幔整体偏重的铁同位素组成,因产出构造环境不同其δ56Fe略有不同:洋中脊玄武岩(MORB)δ56Fe=0.105±0.039‰(2SD,n=46);洋岛玄武岩(OIB)δ56Fe=0.121±0.075‰(2SD,n=61);岛弧玄武岩(IAB)δ56Fe=0.060±0.089‰(2SD,n=25)。地幔部分熔融过程中,铁同位素存在显著分馏,显著不同于其他类  相似文献   

4.
MC-ICP-MS高精度Cu、Zn同位素测试技术   总被引:4,自引:1,他引:3       下载免费PDF全文
过渡族元素同位素是国际上同位素地球化学研究的热点。测试技术的限制是制约过渡元素同位素研究发展的关键。笔者利用Neptune型多接收等离子质谱(MC-ICP-MS),采用Cu、Zn互为内标的方法对仪器的质量歧视进行了校正,对基质效应和测试方法的重现性进行了检验,建立了高精度的Cu、Zn同位素测试技术。在5个月内对实验室标准IMRCu和IMRZn进行了测量,结果分别为δ65CuNIST976=(0.34±0.08)‰(2SD,n=32),δ66ZnJMCZn=(-9.64±0.05)‰(2SD,n=26),δ67ZnJMCZn=(-14.37±0.16)‰(2SD,n=26),δ68ZnJMCZn=(-19.01±0.08)‰(2SD,n=26),分析精度达到国际同类实验室先进水平。对Cu、Zn同位素参考物质进行了对比测量,分析结果与报道值在误差范围内完全一致。  相似文献   

5.
近年来,铜同位素在表生环境和生物地球化学中的应用越来越广泛,尤其是土壤的铜同位素组成可以示踪环境污染物来源及生物地球化学过程。目前,对土壤铜同位素进行研究时,主要以硅酸岩标准物质为标样来衡量土壤样品铜同位素测定的准确性和精确性。但土壤与硅酸岩中铜、基质离子及有机质的含量等存在很大差异(如:硅酸岩中的铜含量80μg/g,一些土壤中的铜含量很低,20μg/g),将硅酸岩标准物质作为标样来监测土壤样品的数据质量缺乏代表性。为了弥补这一缺陷,本文精确测定4个国家土壤标准物质(GBW07443、GBW07425、GBW07427、GBW07389)的铜同位素组成,并将其作为检验土壤样品铜同位素测定过程中的标准。实验中采用高温高压反应釜消解样品,利用AG MP-1M树脂进行纯化,全流程空白2ng,回收率≥98%,通过多接收器电感耦合等离子体质谱仪(MC-ICP-MS)采用标样-样品-标样间插法进行仪器分馏校正,δ~(65)Cu的长期测试外精度优于0.05‰(n=306, 2SD)。GBW07443、GBW07425、GBW07427和GBW07389的铜同位素组成分别为-0.04‰±0.04‰(n=9, 2SD)、-0.07‰±0.05‰(n=12, 2SD)、-0.06‰±0.04‰(n=12, 2SD)、-0.02‰±0.06‰(n=12, 2SD)。这些土壤标准物质的铜同位素组成均位于0附近,大致为自然界土壤铜同位素比值变化范围(-0.5‰~+0.5‰)的中间值,且样品容易获得,其化学和铜同位素组成均一,适合作为监控土壤铜同位素化学及质谱分析数据可靠性的标准物质。  相似文献   

6.
锂同位素研究是非传统稳定同位素地球化学研究的前沿,已广泛应用于从地表到地幔的岩石圈及流体等固体地球科学的研究领域。准确测定锂同位素比值是应用该同位素体系的前提。本文报道了国际上7种常用地质标准物质(BHVO-2、JB-2、BCR-2、AGV-2、NKT-1、L-SVEC、IRMM-016)的锂同位素组成数据。分析中采用硝酸-氢氟酸混合酸消解岩石标准样品,通过3根阳离子交换树脂(AG50W-X8,200~400目)填充的聚丙烯交换柱和石英交换柱对锂进行分离富集,利用Neptune型多接收器电感耦合等离子体质谱(MC-ICPMS)测定锂同位素比值,使用标准-样品交叉法(SSB)校正仪器的质量分馏。实验得到这7种常用地质标准物质的锂同位素组成与测试精度(2SD)分别为:δ7LiBHVO-2—L-SVEC=4.7‰±1.0‰(n=53),δ7LiJB-2—L-SVEC=4.9‰±1.0‰(n=20),δ7LiBCR-2—L-SVEC=4.4‰±0.8‰(n=8),δ7LiAGV-2—L-SVEC=6.1‰±0.4‰(n=14),δ7LiNKT-1—L-SVEC=9.8‰±0.2‰(n=3),δ7LiL-SVEC—L-SVEC=-0.3‰±0.3‰(n=10),δ7LiIRMM-016—L-SVEC=0.0‰±0.5‰(n=10),这些数据在误差范围内与国际上已发表的数据一致。Li同位素分析精度可以达到大约0.5‰,长期的分析精度即外部重现性≤±1.0‰,达到了国际同类实验室水平。7种常用地质标准物质的锂同位素组成数据的发表为锂同位素研究提供了统一的标准,使地质样品的锂同位素数据的质量监控成为可能。在基质效应的研究中,使用不同量的IRMM-016配制的标准溶液过柱,深入探讨了样品量对锂同位素测定值的影响,结果表明,在现有测试精度下,只要分析样品的锂含量达到100μg/L,且不超过树脂的承载量,样品的锂同位素组成在误差范围内与真值吻合,样品量的大小不影响锂同位素测定结果的准确性。  相似文献   

7.
详细报道了在低分辨和高分辨模式下运用MC-ICP-MS进行Fe同位素比值高精度测试的方法,对Fe同位素测定过程中谱峰干扰、基质效应、浓度效应、仪器测试的长期重现性等问题进行了评估,并对两种运行模式的测试结果进行了对比.在95%的可信度范围内,所建方法的外部精度优于0.5ε/ainu,达到国际同类实验室的先进水平,并且低分辨和高分辨两种模式下获得的Fe同位素测试结果是一致的.在此基础上对国家地质标准物质GBW07105(玄武岩)和GBW 07111(花岗闪长岩)进行了Fe同位素测定.相对于Fe同位素国际标样IRMM-014,GBW07105的Fe同位素成分为:ε57Fe=1.9±0.3(20),ε56Fe=1.3±0.2(2σ),ε57/56Fe=0.6±0.1(2σ);GBW 07111的Fe同位素成分为:ε57Fe=1.8±0.4(2σ),ε56Fe=1.2±0.2(2σ),ε57/56Fe=0.6±0.1(2σ).  相似文献   

8.
报道了利用少量AG1-X4阴离子交换树脂分离地质样品中Fe及测定Fe同位素的方法。对少量AG1-X4和AG MP-1树脂的分离效果进行了比较,测定了经过AG1-X4分离后的地质标样BCR-2、BHVO-2、BIR-1a、AGV-2、W-2、GSP-2、COQ-1、DTS-2b、JB-2、Jsd-1、GBW07105和GBW07267的Fe同位素组成,其结果与文献参考值在误差范围内一致。这些数据的发表对于地质样品Fe的化学分离和同位素测定提供了参考依据。此方法可以大大减少化学试剂用量,是一种快速有效分离铁的方法。  相似文献   

9.
多接收器等离子体质谱法Zn同位素比值的高精度测定   总被引:12,自引:3,他引:9       下载免费PDF全文
详细报道了Zn同位素比值的多接收器等离子体质谱(MC-ICP-MS)高精度测定方法,包括:MC-ICP-MS Zn同位素测量过程中的质量歧视校正、同质异位素干扰评估、基质效应调查和同位素测量的长期重现性检验.研究表明,在测定条件下,运用标样一样品交叉法能有效地进行仪器质量歧视校正.同质异位素干扰的评估通过3种方式进行,即:在高分辨状态下同质异位数干扰信号的直接测定,低分辨状态下Zn同位素原始数据间相关关系的检验和低分辨下浓度梯度效应研究.结果表明,在低分辨模式下,尽管66Zn、67Zn、68Zn的同质异位素干扰信号很小,但的确存在,要获得准确同位素比值,必须使标样和样品的浓度在合适的范围内匹配.在基质效应方面,主要考察Fe对Zn同位素比值测定的影响.结果表明,当溶液中Fe/Zn(质量比)不大于0.2时,Fe对Zn同位素比值测定无影响.重复性测定中,δ66ZnGSB-Romil=6.96‰±0.11‰(2sd),δ67ZnGSB-Romil=10.4‰±0.20‰(2sd),δ68ZnGSB-Romil=13.8‰±0.22‰(2sd),达到国际同类实验室先进水准.运用所建立的方法,对地质岩石成分分析国家标准物质GBW 07270(闪锌矿)进行了Zn同位素平均成分测定为:δ66Zn=6.71‰±0.03‰(20),δ67Zn=10.08‰±0.05‰(20),δ68Zn=13.37‰±0.07‰(2σ).  相似文献   

10.
使用AGMP-1M阴离子交换树脂提纯样品中的Fe同位素,利用Nu1700大型多接收等离子体质谱在高分辨率模式下测定铁同位素比值,采用标样-样品交叉法校正仪器的质量歧视效应,对回收率、化学流程本底、酸度效应、浓度效应进行了检验,建立了可靠的高精度铁同位素分析技术。本文测定了常用地质标准样品(BCR-2,BHVO-2,AGV-2,GSR-2,GSR-3)的Fe同位素组成,测定结果与文献报道值在误差范围内一致,其测试精度优于(BCR-2,BHVO-2,AGV-2,GSR-3)0.03‰(2SD)。GSR-2可能受Fe含量较低(TFe_2O_3=4.95%)和均一性的影响,获得的δ~(56)Fe和δ~(57)Fe的测试精度分别为0.05‰和0.07‰(2SD)。  相似文献   

11.
The present study evaluates several critical issues related to precision and accuracy of Cu and Zn isotopic measurements with application to estuarine particulate materials. Calibration of reference materials (such as the IRMM 3702 Zn) against the JMC Zn and NIST Cu reference materials were performed in wet and/or dry plasma modes (Aridus I and DSN‐100) on a Nu Plasma MC‐ICP‐MS. Different mass bias correction methods were compared. More than 100 analyses of certified reference materials suggested that the sample‐calibrator bracketing correction and the empirical external normalisation methods provide the most reliable corrections, with long term external precisions of 0.06 and 0.07‰ (2SD), respectively. Investigation of the effect of variable analyte to spike concentration ratios on Zn and Cu isotopic determinations indicated that the accuracy of Cu measurements in dry plasma is very sensitive to the relative Cu and Zn concentrations, with deviations of δ65Cu from ?0.4‰ (Cu/Zn = 4) to +0.4‰ (Cu/Zn = 0.2). A quantitative assessment (with instrumental mass bias corrections) of spectral and non‐spectral interferences (Ti, Cr, Co, Fe, Ca, Mg, Na) was performed. Titanium and Cr were the most severe interfering constituents, contributing to inaccuracies of ?5.1‰ and +0.60‰ on δ68/64Zn, respectively (for 500 μg l?1 Cu and Zn standard solutions spiked with 1000 μg l?1 of Ti or Cr). Preliminary isotopic results were obtained on contrasting sediment matrices from the Scheldt estuary. Significant isotopic fractionation of zinc (from 0.21‰ to 1.13‰ for δ66Zn) and copper (from ?0.38‰ to 0.23‰ for δ65Cu), suggest a control by physical mixing of continental and marine water masses, characterized by distinct Cu and Zn isotopic signatures. These results provide a stepping‐stone to further evaluate the use of Cu and Zn isotopes as biogeochemical tracers in estuarine environments.  相似文献   

12.
The commonly used, but no longer available, reference materials NIST SRM 976 (Cu) and ‘JMC Lyon’ (Zn) were calibrated against the new reference materials ERM®‐AE633, ERM®‐AE647 (Cu) and IRMM‐3702 (Zn), certified for isotope amount ratios. This cross‐calibration of new with old reference materials provides a continuous and reliable comparability of already published with future Cu and Zn isotope data. The Cu isotope amount ratio of NIST SRM 976 yielded δ65/63Cu values of ?0.01 ± 0.05‰ and ?0.21 ± 0.05‰ relative to ERM®‐AE633 and ERM®‐AE647, respectively, and a δ66/64ZnIRMM‐3702 value of ?0.29 ± 0.05‰ was determined for ‘JMC Lyon’. Furthermore, we separated Cu and Zn from five geological reference materials (BCR‐2, BHVO‐2, BIR‐1, AGV‐1 and G‐2) using a two‐step ion‐exchange chromatographic procedure. Possible isotope fractionation of Cu during chromatographic purification and introduction of resin‐ and/or matrix‐induced interferences were assessed by enriched 65Cu isotope addition. Instrumental mass bias correction for the isotope ratio determinations by MC‐ICP‐MS was performed using calibrator‐sample bracketing with internal Ni doping for Cu and a double spike approach for Zn. Our results for the five geological reference materials were in very good agreement with literature data, confirming the accuracy and applicability of our analytical protocol.  相似文献   

13.
This paper presents an adapted anion exchange column chemistry protocol which allowed separation of high-purity fractions of Cu and Zn from geological materials. Isobaric and non-spectral interferences were virtually eliminated for consequent multiple-collector ICP-MS analysis of the isotopic composition of these metals. The procedure achieved ∼ 100% recoveries, thus ensuring the absence of column-induced isotopic fractionation. By employing these techniques, we report isotopic analyses for Cu and Zn from five geological reference materials: BCR-027 blende ore (BCR), δ65Cu = 0.52 ± 0.15‰ (n = 10) and δ66Zn = 0.33 ± 0.07‰ (n = 8); BCR-030 calcined calamine ore (BCR), δ66Zn = -0.06 ± 0.09‰ (n = 8); BCR-1 basalt (USGS), δ66Zn = 0.29 ± 0.12‰ (n = 8); NOD-P-1 manganese nodule (USGS), δ65Cu = 0.46 ± 0.08‰ (n = 10) and δ66Zn = 0.78 ± 0.09‰ (n = 9); SU-1 Cu-Co ore (CCRMP), δ65Cu = -0.018 ± 0.08‰ (n = 10) and δ66Zn = 0.13 ± 0.17‰ (n = 6). All uncertainties are ± 2s; copper isotope ratios are reported relative to NIST SRM-976, and zinc isotope ratios relative to the Lyon-group Johnson Matthey metal (batch 3-0749 L) solution, JMC Zn. These values agree well with the limited data previously published, and with results reported for similar natural sample types. Samples were measured using a GVi IsoProbe MC-ICP-MS, based at the Natural History Museum, London. Long-term measurement reproducibility has been assessed by repeat analyses of both single element and complex matrix samples, and was commonly better than ± 0.07‰ for both δ66Zn and δ65Cu.  相似文献   

14.
Iron, Cu and Zn stable isotope systems are applied in constraining a variety of geochemical and environmental processes. Secondary reference materials have been developed by the Institute of Geology, Chinese Academy of Geological Sciences (CAGS), in collaboration with other participating laboratories, comprising three solutions (CAGS‐Fe, CAGS‐Cu and CAGS‐Zn) and one basalt (CAGS‐Basalt). These materials exhibit sufficient homogeneity and stability for application in Fe, Cu and Zn isotopic ratio determinations. Reference values were determined by inter‐laboratory analytical comparisons involving up to eight participating laboratories employing MC‐ICP‐MS techniques, based on the unweighted means of submitted results. Isotopic compositions are reported in per mil notation, based on reference materials IRMM‐014 for Fe, NIST SRM 976 for Cu and IRMM‐3702 for Zn. Respective reference values of CAGS‐Fe, CAGS‐Cu and CAGS‐Zn solutions are as follows: δ56Fe = 0.83 ± 0.07 and δ57Fe = 1.20 ± 0.13, δ65Cu = 0.57 ± 0.06, and δ66Zn = ?0.79 ± 0.12 and δ68Zn = ?1.65 ± 0.24, respectively. Those of CAGS‐Basalt are δ56Fe = 0.15 ± 0.07, δ57Fe = 0.22 ± 0.10, δ65Cu = 0.12 ± 0.08, δ66Zn = 0.17 ± 0.13, and δ68Zn = 0.34 ± 0.26 (2s).  相似文献   

15.
海洋沉积物的铁和锌同位素测定   总被引:2,自引:0,他引:2  
介绍海洋沉积物Fe和Zn同位素化学前处理及测定方法,报道南海西部夏季上升流区两个沉积物柱样的Fe和Zn同位素组成。样品采用HF+HNO3+HClO4常压消解,经脱盐后,转化为氯化物形式并经离子交换柱分离纯化后,用多接收器等离子体质谱法测定Fe和Zn同位素比值。该前处理方法可以快捷地实现海洋沉积物的消解、有机质的去除和海盐脱离;结合相关测试流程,可获得较高的δ56Fe(0.10‰,2SD)和δ66Zn分析精度(0.11‰,2SD)。两个沉积物柱样的δ56Fe值(相对于IRMM-014)和δ66Zn值(相对于JMC3-0749C)随深度变化不明显,两柱之间也无明显差异。总体上,南海西部上升流区1~2 ka以来的沉积物δ56Fe值(0.04‰~0.20‰)和δ66Zn值(0.12‰~0.30‰)与已报道的黄土和气溶胶、火成岩以及大部分海洋沉积物接近,明显高于静海相海洋沉积物的δ56Fe值。  相似文献   

16.
This work presents isotopic data for the non-traditional isotope systems Fe, Cu, and Zn on a set of Chicxulub impactites and target lithologies with the aim of better documenting the dynamic processes taking place during hypervelocity impact events, as well as those affecting impact structures during the post-impact phase. The focus lies on material from the recent IODP-ICDP Expedition 364 Hole M0077A drill core obtained from the offshore Chicxulub peak ring. Two ejecta blanket samples from the UNAM 5 and 7 cores were used to compare the crater lithologies with those outside of the impact structure. The datasets of bulk Fe, Cu, and Zn isotope ratios are coupled with petrographic observations and bulk major and trace element compositions to disentangle equilibrium isotope fractionation effects from kinetic processes. The observed Fe and Cu isotopic signatures, with δ56/54Fe ranging from ?0.95‰ to 0.58‰ and δ65/63Cu from ?0.73‰ to 0.14‰, mostly reflect felsic, mafic, and carbonate target lithology mixing and secondary sulfide mineral formation, the latter associated to the extensive and long-lived (>105 years) hydrothermal system within Chicxulub structure. On the other hand, the stable Zn isotope ratios provide evidence for volatility-governed isotopic fractionation. The heavier Zn isotopic compositions observed for the uppermost part of the impactite sequence and a metamorphic clast (δ66/64Zn of up to 0.80‰ and 0.87‰, respectively) relative to most basement lithologies and impact melt rock units indicate partial vaporization of Zn, comparable to what has been observed for Cretaceous-Paleogene boundary layer sediments around the world, as well as for tektites from various strewn fields. In contrast to previous work, our data indicate that an isotopically light Zn reservoir (δ66/64Zn down to ?0.49‰), of which the existence has previously been suggested based on mass balance considerations, may reside within the upper impact melt rock (UIM) unit. This observation is restricted to a few UIM samples only and cannot be extended to other target or impact melt rock units. Light isotopic signatures of moderately volatile elements in tektites and microtektites have previously been linked to (back-)condensation under distinct kinetic regimes. Although some of the signatures observed may have been partially overprinted during post-impact processes, our bulk data confirm impact volatilization and condensation of Zn, which may be even more pronounced at the microscale, with variable degrees of mixing between isotopically distinct reservoirs, not only at proximal to distal ejecta sites, but also within the lithologies associated with the Chicxulub impact crater.  相似文献   

17.
Zhaxikang is one large Sb–Pb–Zn–Ag deposit located in the North Himalaya of southern Tibet. To date, the genesis of this deposit still remains controversial. Here, we present new pyrite Fe and sphalerite Zn isotopic data for the first three stages of mineralization, Fe–Zn isotopic data for Mn–Fe carbonate that formed during the first two stages of mineralization, and Zn isotopic data for the slate wall rocks of the Jurassic Ridang Formation to discuss the genesis of the Zhaxikang deposit. The overall δ56Fe and δ66Zn values range from −0.80‰ to 0.43‰ and from −0.03‰ to 0.38‰, respectively. The δ56Fe values of Mn–Fe carbonates are lighter than those of associated pyrite in six mineral pairs, indicating that the iron carbonates are preferentially enriched in light Fe isotopes relative to pyrite. The sphalerite has lighter δ66Zn values than associated Mn–Fe carbonates in three mineral pairs.The δ56Fe values of pyrite that formed during the first three stages of mineralization gradually increase from stage 1 (−0.33‰ to −0.09‰) through stage 2 (−0.30‰ to 0.19‰) to stage 3 (0.16‰–0.43‰). In comparison, the sphalerite that formed during these stages has δ66Zn values that gradually decrease from stage 1 (0.16‰–0.35‰) through stage 2 (0.09‰–0.23‰) to stage 3 (−0.03‰ to 0.22‰). These data, in conjunction with the observations of hand specimens and thin sections, suggest that the deposit was overprinted by a second pulse of mineralization. This overprint would account for these Fe–Zn isotopic variations as well as the kinetic Rayleigh fractionation that occurred during mineralization. The temporally increasing δ56Fe and decreasing δ66Zn values recorded in the deposit are also coincident with an increase in alteration, again supporting the existence of two pulses of mineralization. The δ56Fe values of the first pulse of ore-forming fluid were calculated using theoretical equations, yielding values of −0.54‰ to −0.34‰ that overlap with those of submarine hydrothermal solutions (−1‰ to 0‰). However, the δ56Fe values of the stage 3 pyrite are heavier than those of typical submarine hydrothermal solutions, which suggests that the second pulse of mineralization was probably derived from a magmatic hydrothermal fluid. In addition, the second pulse of ore-forming fluid has brought some Fe and taken away parts of Zn, which results the lighter δ66Zn values of sphalerite and heavier δ56Fe values of pyrite from the second pulse of mineralization. Overall, the Zhaxikang deposit records two pulses of mineralization, and the overprint by the second pulse of mineralization causes the lighter δ66Zn values and heavier δ56Fe values of modified samples.  相似文献   

18.
过渡族金属元素同位素分析方法及其地质应用   总被引:21,自引:0,他引:21  
蒋少涌 《地学前缘》2003,10(2):269-278
由于同位素分析方法的改进和多接收电感耦合等离子体质谱仪 (MC ICP MS)的应用 ,近年来过渡族金属元素 (Cu ,Zn和Fe)同位素地球化学有了长足进步 ,成为国际地学领域的一个前沿研究方向。Cu同位素在自然界中的变化最大 ,δ65Cu值为 - 3.70‰~ +2 .0 5‰ ;Zn和Fe同位素变化比Cu同位素变化小 ,δ66Zn值为 - 0 .6 4‰~ +1.16‰ ,而δ56Fe值为 - 1.6 2‰~ +0 .91‰。自然界中各种无机过程 (从高温到低温 )和生物有机过程均能使Cu ,Zn和Fe同位素发生分馏。Cu、Zn和Fe在自然界中广泛分布于各类矿物、岩石、流体和生物体中 ,并广泛参与成岩成矿作用、热液活动和生命活动过程。因此 ,这些过渡族金属元素同位素已在陨石和宇宙化学、矿床学 ,海洋学和生物学等领域的研究中取得了显著成效 ,并将成为地球科学中具有巨大应用前景的一种新的地球化学手段。  相似文献   

19.
Measuring Hg Isotopes in Bio-Geo-Environmental Reference Materials   总被引:1,自引:0,他引:1  
With the emergence of new analytical techniques and the expansion of scientific fields explored by using mercury isotopes, the community needs reference materials (RM) to validate and assure the accuracy of the results. The present work investigates (1) the characterisation of secondary RM in order to validate analytical systems, (2) the effects of two complex matrices on isotopic determination using stannous chloride cold vapour generation coupled to MC-ICP-MS (CV-MC-ICP-MS), (3) the effects of multiple digestion techniques for total Hg extraction and (4) the characterisation of nine geo-bio-environmental RM. Two secondary mono-elemental RMs analysed using two different analytical setups yielded isotopic compositions on δ202Hg of −3.54 ± 0.27‰ (CRPG-F65A, 2SD, n = 38) and +2.59 ± 0.19‰ (CRPG-RL24H, 2SD, n = 30) relative to the CRM NIST SRM 3133. These two RMs cover the whole range of Hg isotopic fractionation in natural samples and are made available to the scientific community. Complex fly ash and hydroxysulfate green rust matrices were synthesised, spiked with NIST SRM 3133, then digested and finally analysed versus the mono-elemental NIST SRM 3133 to show potential effect of these complex matrices during CV-MC-ICP-MS. Three digestions techniques, including traditional acid digestion, microwave digestion and high pressure-high temperature digestion, were applied to the lichen RM BCR-482 in order to compare advantages and drawbacks of these methods. Finally, the isotopic compositions of nine RMs including soils (NIST SRM 2711; GXR-2; GSS-4), sediment (GSD-10), jasperoid (GXR-1), ore deposit (GXR-3), fly ashes (BCR-176; BCR-176R) and lichen (BCR-482) are reported. These selected materials have δ202Hg values ranging from −1.75‰ to +0.11‰. Some RMs also presented mass-independent fractionation with Δ199Hg and Δ201Hg of up to −0.6‰.  相似文献   

20.
In this study the homogeneity of the zinc isotopic composition in the NIST SRM 683 reference material was examined by measuring the Zn isotopic signature in microdrilled sample powders from two metal nuggets. Zinc was purified using AG MP‐1M resin and then measured by MC‐ICP‐MS. Instrumental mass bias was corrected using the “sample‐standard bracketing” method and empirical external normalisation with Cu doping. After evaluating the potential effects of varying acid mass fractions and different matrices, high‐precision Zn isotope data were obtained with an intermediate measurement precision better than ± 0.05‰ (δ66Zn, 2s) over a period of 5 months. The δ66ZnJMC‐Lyon mean values of eighty‐four and fourteen drilled powders from two nuggets were 0.11 ± 0.02‰ and 0.12 ± 0.02‰, respectively, indicating that NIST SRM 683 is a good isotopic reference material with homogeneous Zn isotopes. The Zn isotopic compositions of seventeen rock reference materials were also determined, and their δ66Zn values were in agreement with most previously published data within 2s. The δ66Zn values of most of the rock reference materials analysed were in the range 0.22–0.36‰, except for GSP‐2 (1.07 ± 0.06‰, n = 12), NOD‐A‐1 (0.96 ± 0.03‰, = 6) and NOD‐P‐1 (0.78 ± 0.03‰, = 6). These comprehensive data should serve as reference values for quality assurance and interlaboratory calibration exercises.  相似文献   

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